BirdList

public class BirdList {

    private Node head;

    public BirdList()
    {
        head = null;
    }

    // --- INSERT METHODS --- //
    public void insert(String n)
    {
        if (head == null) {
            insertFirst(n);
            return;
        }
        if (find(n)) {
            int pos = findIndex(n);
            int start = 0;
            Node ref = head;
            while (start < pos) {
                ref = ref.next;
                start++;
            }
            ref.frequency++;
        }
        else insertLast(n);
    }

    public void insertFirst(String n)
    {
        Node newNode = new Node(n);
        newNode.next = head;
        head = newNode;
    }

    public void insertLast(String n)
    {
        Node newNode = new Node(n);
        if (head == null)
            head = newNode;
        else if (head.next == null)
            head.next = newNode;
        else {
            Node ref = head;
            while (ref.next != null)
            {
                ref = ref.next;
            }
            ref.next = newNode;
        }
    }

    // --- Size Method --- //
    public int getSize()
    {
        Node ref = head;
        int size = 0;
        while (ref != null)
        {
            size++;
            ref = ref.next;
        }
        return size;
    }

    // --- FIND METHODS --- //
    public boolean find(String n) // Returns true if name is found in list
    {
        Node ref = head;
        while (ref != null)
        {
            if (ref.name.equals(n))
                return true;
            ref = ref.next;
        }
        return false;
    }

    public int findIndex(String n)
    {
        int index = -1;
        if (!find(n))
            return index;
        else {
            Node ref = head;
            index = 0;
            while (ref != null) {

                if (ref.name.equals(n))
                    break;
                index ++;
                ref = ref.next;
            }
            return index;
        }
    }

    // --- SORT METHODS --- //
    public void sort()
    {
        for (Node ref = head; ref != null; ref = ref.next) {
            for (Node ref2 = ref.next; ref2 != null; ref2 = ref2.next) {
                if (ref.frequency < ref2.frequency) {
                    String tempName = ref.name;
                    int tempFreq = ref.frequency;
                    ref.name = ref2.name;
                    ref.frequency = ref2.frequency;
                    ref2.name = tempName;
                    ref2.frequency = tempFreq;
                }
            }
        }
    }
    public void remove(String n)
    {
        if (find(n))
        {
            Node ref = head;
            Node prev = head;
            while (!ref.name.equals(n)) {
                prev = ref;
                ref = ref.next;
            }
            if (ref == head)
                head = head.next;
            prev.next = ref.next;
        }
    }



    // --- PRINT METHODS --- ///
    public void printList()
    {
        Node ref = head;
        while (ref != null)
        {
            System.out.println(ref.name + ": " + ref.frequency);
            ref = ref.next;
        }
    }

    class Node {
        private String name;
        private int frequency;
        private Node next;

        public Node(String n) {
            this.name = n;
            this.frequency = 1;
            next = null;
        }
    }
}